1. Field of the Invention
The present invention relates to an energizing device for a press die, and more particularly, to an energizing device for a press die that can be easily attached and detached and that is provided to be sufficiently safe.
2. Description of the Background Art
A conventional energizing device for a press die is shown in FIG. 7 and FIG. 8. In such a press die, a workpiece, W is mounted on a supporting portion 102 of a lower die 101 such that a hole 105 may be formed in a piercing manner on a lateral surface of the workpiece W by means of a punch 104 that is horizontally arranged with respect to a passive cam 103 performing sliding movements in a lateral direction, wherein the passive cam 103 is driven by an active cam 107 of an upper die 106.
In FIG. 7, the mold assumes a condition at a dead bottom center, and upon completion of the hole forming process, the upper die 106 is raised, and in the absence of pressuring force applied by the active cam 107, the passive cam 103 is retracted through an energizing force of a coil spring 108 that is provided at a lower portion of the cam until it abuts against a terminating surface 110 of a wall body 109.
Here, the coil spring 108 which functions to retract the passive cam 103 is arranged in that it is outwardly fitted to a guide pin 112 that is formed to be extruded in a horizontal condition by being screwed to a rising wall 111 such that one end surface abuts against the rising wall 111, and the other end surface is made to abut against a supporting plate 113 wherein this supporting plate 113 is fixed to the passive cam 103 by means of a bolt 114.
The supporting plate 113 includes a groove 115 that is open in a downward direction such that the guide pin 112 may be taken out at the time of performing maintenance or inspection. Due to the groove 115 in the supporting plate 113, one part of the coil spring 108 abuts against the supporting plate 113, while a remaining part of the coil spring 108 extends over the groove 115 and is not supported by the supporting plate 113 such that fit of the coil spring 108 with respect to the supporting plate 113 becomes unstable. Consequently, the coil spring 108 can no longer be disposed in a horizontal condition, which results in cases in which the coil spring 108 abuts against an outer periphery of the guide pin 112, such that the guide pin 112 is worn or the coil spring 108 is deformed or seized so that the energizing device may not be completely actuated.
It is desirable to have an energizing device for a press die which is capable of eliminating the above-mentioned drawbacks such as the occurrence of deformation or seizing of the coil spring or damage to the guide pin, and which presents favorable operatability by enabling the coil spring or the guide pin to be easily attached or detached at the time of performing maintenance or inspection without the necessity of detaching the press die from the press machine while such operations can be performed in a safe manner.
In view of these facts, the energizing device for a press die according to the present invention has been devised with an energizing body for energizing a press member, by being disposed between two members to abut against both surfaces thereof so as to enable easy attaching/detaching of the energizing body while maintaining a condition in which the energizing body is attached to a press machine, wherein one of the members is provided with a plug of an outer diameter that is larger than an outer diameter of the energizing body and abutting against an end surface of the energizing body.
The energizing device for a press die of the present invention is particularly arranged in that the plug is threaded into the one member in order to be attached to the one member. A hexagonal taking-out hole is formed in a concave manner on a surface of the plug opposite to a surface of the plug which abuts with the energizing body.
Moreover, the press die includes a taking-out hole of an inner diameter that is larger than the outer diameter of the plug and which is pierced through a wall body of a lower die that is disposed so as to oppose the plug. Further, the press die may include a safety device for preventing jumping-out of the plug and/or the energizing body. The safety device is a safety plate that may be provided in a freely attachable/detachable manner to the one member so as to oppose the plug, or may be provided in a freely attachable/detachable manner on the wall body so as to oppose the plug.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.